1. Technical Field
The present invention relates to a liquid ejecting head and a liquid ejecting apparatus using the liquid ejecting head.
2. Related Art
A liquid ejecting head that ejects liquid through nozzle orifices is used in various kinds of liquid ejecting apparatuses. Examples of them are: an image recording apparatus such as a printer, a liquid ejecting apparatus used in the production of a color filter for a liquid crystal display device, etc. A certain type of a liquid ejecting head ejects liquid in the form of droplets when voltage is applied to piezoelectric elements provided on a surface of a diaphragm plate. The voltage is applied thereto so as to cause the piezoelectric elements to get deformed in accordance with driving signals supplied from a driving circuit. Such a liquid ejecting head is provided with a head unit that includes the diaphragm plate, pressure generation chambers, nozzle orifices, and a manifold. The diaphragm plate constitutes a ceiling part of each of the pressure generation chambers. The diaphragm plate, a flow passage formation substrate, a nozzle plate, which is a plate through which the nozzle orifices are formed, are laid one on another for manufacturing the head unit. For example, an ink-jet recording head manufactured by co-firing plate members made of ceramics is known as an example of such a liquid ejecting head as disclosed in JP-A-10-286956.
If insulating ceramics is used as the material of each of a diaphragm plate, a flow passage formation substrate, and a nozzle plate, and if these insulating ceramic plate members are co-fired, the insulating ceramics will be charged due to piezoelectric-element electrification or due to static electricity. Therefore, there is a risk that the dielectric breakdown of the diaphragm plate might occur, or a driving circuit may get damaged through the electrodes of the piezoelectric elements.